Underwater fluid-operated horn



March 1964 L. N. LIEBERMANN ETAL 3,125,061

UNDERWATER FLUID-OPERATED HORN Filed Aug. 10. 1961 Ill i i a FIGURE 3 l2 I5 20 '9 FIGURE 2 l3l/ INV EN TOR.

wink v.

United States Patent Calif.

Filed Aug. 10, 1961, Ser. No. 130,698 2 Claims. (Cl. 116-27) This invention relates to a horn for underwater use and, more particularly, to a moving diaphragm horn actuated by compressed fluid for underwater use.

Prior fluid-operated horns are intended for use in air, rather than under water. These are designed for emitting warning signals, for trains, buses, trucks, etc. Air horns, when immersed in water, either fail to emit any sound or ernit only a very weak sound. Hence, they cannot be used as suitable sound sources for underwater applications.

The present invention is a fluid-operated horn which emits an intense tone While immersed in water. Previous horns emit strong tones in air, but when submerged in water, they either cease operating or emit a very weak signal. The present invention emits a strong tone in air and continues to emit a strong tone When submerged even to depths of several hundred feet.

An object of the present invention is the provision of an intense underwater sound source for signaling or communication under water.

Another object is to provide an underwater sound source operating without batteries or electrical equipment.

Another object of the invention is to provide a selfcontained portable underwater sound source without the need of electrical cables, hoses or pipes.

A further object of the present invention is the provision of a fluid-operated sound source which will operate without adjustment over a Wide variety of water depths from shallow to deep water.

A final object is to provide a sound source for underwater use which can be readily keyed for communication using Morse code.-

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIG. 1 is an exploded view, partly in top plan of the apparatus;

FIG. 2 is a diametrical cross sectional elevation of the device;

FIG. 3 is a partial diametrical cross sectional elevation of the device showing a modification thereof.

Referring now to the drawings wherein like reference characters designate like parts throughout the several views, there is shown in FIGURE 1 a clamping ring 11, a diaphragm 12, and a backing plate 13. A slightly raised ring 15, fixed to the backing plate 13 is in full and intimate contact with the diaphragm when the structure is assembled. Centrally disposed smooth hole 16 is provided for the exhaust of compound fluid as hereinafter described. Threaded hole 17, offset laterally from hole 16 is provided to receive the interior and exterior threaded pipe nipple 14 through which compressed fluid may be introduced into the device. The screw 20 which is a loose fit in the interior threaded passage of the pipe nipple 14, only partially blocks this passage in pipe nipple 14 cansing a slow leak. Corresponding mounting holes 18 and 21 are provided in the clamping ring 11 and backing plate 13, respectively, whereby these two parts are screwed or riveted together, thus clamping the diaphragm 12 to the backing plate 13.

3,125,%l Patented Mar. 17, 1964 ice The diaphragm 12 is securely pressed against the backing plate 13 by rivets or screws as is shown in FIG. 2. The diaphragm is composed of thin sheet material such as beryllium, copper, Phosphor bronze, or plastics which will not be corroded by the action of sea Water and which will stand repeated flexing. The annular ring 15, being raised only a minute amount, can be embossed, machined, or moulded as an integral part of the backing plate.

FIGURE 3 illustrates a modification in which the annular ring 15 is embossed in the diaphragm rather than in the backing plate. In this manner the backing plate can be a simple plane disc requiring no special machining or moulding.

Operation of the horn, as shown in FIGS. 1 and 2, is as follows: Compressed fluid enters through orifice 19, formed in the threaded nipple 14, and is reduced in pressure by the slow leak screw 29. The incoming fluid pressure enters the cavity 23 formed between diaphragm 12 and backing plate 13, raises the diaphragm 12, thus creating an opening over the ring 15, and allows the fluid to exit at hole 16. The loss of fluid through smooth hole 16 causes a pressure drop in the cavity 23, thus allowing the diaphragm to return to its normal position, closing the gap between ring 15 and the diaphragm 12, and the cycle is repeated.

When the modified diaphragm 12' and backing plate 13, wherein ring 15' is embossed in diaphragm 12, are inserted in the horn structure shown in FIGS. 1 and 2, the operation is similar to that described above except that now the raising of the diaphragm 12' creates the opening under the ring 15 and the fluid exhausts, as before, through smooth hole 16.

It is essential to underwater sound generation that the cavity 23 be of extremely small volume in order that a readily compressible fluid such as air is able to compress the less compressible water by means of the moving diaphragm to produce sound. The present structure achieves the smallest cavity 23 by making the backing plate 13 a plane disc practically in contact with a plane diaphragm 12 being separated only a small amount by the raised ring 15.

Another requirement for good eiiiciency in any diaphragm-operated sound source is the isolation of radiated sound from either the front or back side of the diaphragm. All horns designed for operation in air accomplish this isolation by completely enclosing one side of the diaphragm, utilizing only the side from which the driving fluid is exhausting, as the sound source' The present construction reverses this procedure utilizing the exhaustingfluid (for example, air) to dampen or absorb the sound, one the exit side of the horn; the exhaust fluid in the form of bubbles utilizes the known fact that bubbles under water oiier effective sound absorption. By this means only one side of the diaphragm is caused to radiate sound.

In order for the horn to sound at great water depths the Working pressure must be elevated, compared to that required at shallow depths. Initially, at great depths the horn will not sound, but the slow leak 20 will allow the pressure to build up from the supply tank to the level required for sound radiation, and the horn will commence operation and continue to operate thereafter. If a conventional diaphragm-type pressure reducer were utilized, the fluid pressure would remain constant and the horn would operate efliciently at only a single water depth.

Interruption of the tone for signaling purposes, for example with Morse code, is achieved by blocking the opening 16 with a finger, or other suitable means.

It is seen that the device described above has as its function the production of an underwater sound signal utilizing compressed fluid as its source of power. This provides a compact, simple device for signaling or other purposes of underwater communication.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the a cylindrical cavity formed between said inner face of means for introducing compressed operating fluid at a invention, and it is intended to cover all changes and 5 reduced pressure through said threaded hole in said modifications of examples of the invention herein chosen backing plate to said annular cavity; and for the purposes of the disclosure Which do not consti means for exhausting operating fluid from said cylindritute departures from the spirit and scope of the invention. cal cavity through said backing plate, said means What is claimed is: comprising said centrally disposed hole whereby the 1. An underwater fluid operated ho om ri ing; sound emitting function of said horn is performed by a substantially rigid circular backing l t having a the substantially full Water contact area of the outer centrally disposed hole passing therethrough, a face of Said diaphragm and the reduced PYBSSUTC threaded hole passing therethrough parallel to and comp Operating fluid is illtlodllcfid between a laterally offset from said centrally disposed hole, diaphragm and Said hacking Plate and than eXhau-Sted and an annular raised ring formed in one face of through Said hacking Plate in a direction y from said plate, said ring being concentric with said central hole and having a radius less than the offset said backing plate thus supporting and enhancing the pressure Waves emitted by said diaphragm.

distance between said central hole and said threaded 1 AH uhdfirwatel horn as claimed in claim 1 fulthfil' hole; characterized by having said annular raised ring formed a flexible vibrating diaphragm hermetically sealed to Oh the under surface of Said flexible diaphragm instead the periphery of said one face of said backing plate, of 011 the PP Surface of Said backing P the inner face of said diaphragm being in contact with said annular raised ring and the outer face of said diaphragm being in substantially full area-contact References Cited in the file of this patent UNITED STATES PATENTS with the Water in which the horn is submerged; 12, 57 Shaw 11, 1 79 a small volume annular cavity formed between said 2,281,539 Grover Apr. 28, 1942 inner face of said sealed diaphragm and said one 2,642,028 Johnson June 16, 1953 face of said plate, exteriorly of said raised ring; 2,918,895 Buell Dec. 29, 1959 

1. AN UNDERWATER FLUID OPERATED HORN COMPRISING: A SUBSTANTIALLY RIGID CIRCULAR BACKING PLATE HAVING A CENTRALLY DISPOSED HOLE PASSING THERETHROUGH, A THREADED HOLE PASSING THERETHROUGH PARALLEL TO AND LATERALLY OFFSET FROM SAID CENTRALLY DISPOSED HOLE, AND AN ANNULAR RAISED RING FORMED IN ONE FACE OF SAID PLATE, SAID RING BEING CONCENTRIC WITH SAID CENTRAL HOLE AND HAVING A RADIUS LESS THAN THE OFFSET DISTANCE BETWEEN SAID CENTRAL HOLE AND SAID THREADED HOLE; A FLEXIBLE VIBRATING DIAPHRAGM HERMETICALLY SEALED TO THE PERIPHERY OF SAID ONE FACE OF SAID BACKING PLATE, THE INNER FACE OF SAID DIAPHRAGM BEING IN CONTACT WITH SAID ANNULAR RAISED RING AND THE OUTER FACE OF SAID DIAPHRAGM BEING IN SUBSTANTIALLY FULL AREA-CONTACT WITH THE WATER IN WHICH THE HORN IS SUBMERGED; A SMALL VOLUME ANNULAR CAVITY FORMED BETWEEN SAID INNER FACE OF SAID SEALED DIAPHRAGM AND SAID ONE FACE OF SAID PLATE, EXTERIORLY OF SAID RAISED RING; A CYLINDRICAL CAVITY FORMED BETWEEN SAID INNER FACE OF SAID DIAPHRAGM AND SAID ONE FACE OF SAID BACKING PLACE, INTERIORLY OF SAID RAISED RING; MEANS FOR INTRODUCING COMPRESSED OPERATING FLUID AT A REDUCED PRESSURE THROUGH SAID THREADED HOLE IN SAID BACKING PLATE TO SAID ANNULAR CAVITY; AND MEANS FOR EXHAUSTING OPERATING FLUID FROM SAID CYLINDRICAL CAVITY THROUGH SAID BACKING PLATE, SAID MEANS COMPRISING SAID CENTRALLY DISPOSED HOLE WHEREBY THE SOUND EMITTING FUNCTION OF SAID HORN IS PERFORMED BY THE SUBSTANTIALLY FULL WATER CONTACT AREA OF THE OUTER FACE OF SAID DIAPHRAGM AND THE REDUCED PRESSURE COMPRESSED OPERATING FLUID IS INTRODUCED BETWEEN SAID DIAPHRAGM AND SAID BACKING PLATE AND THEN EXHAUSTED THROUGH SAID BACKING PLATE IN A DIRECTION AWAY FROM SAID BACKING PLATE THUS SUPPORTING AND ENHANCING THE PRESSURE WAVES EMITTED BY SAID DIAPHRAGM. 